The 16th International Oil, Gas, Refining & petrochemical Exhibition (Iran Oil Show 2011) will open on April 15 and will run till April 19. Iran Oil Show 2011, the largest oil, gas and petrochemicals exhibition in the Middle East, will be held at the Tehran Permanent International Fairgrounds. Some 927 domestic and 580 foreign companies from 40 countries such as Austria, Spain, Australia, England, Italy, Germany, Turkey, Denmark, Russia, France, the Netherlands, India, Singapore, Japan, China, Taiwan, Thailand, the United Arab Emirates, Canada, and Brazil will take part in the event, Iranian News Agency (IRNA) reported. The number of the participating countries shows 20 percent increase in comparison to the previous edition, while the number of attending firms has risen by 22 percent